Postgres Plus Advanced Server provides the standard SQL type BOOLEAN. BOOLEAN can have one of only two states: “true” or “false”. A third state, “unknown”, is represented by the SQL null value.

Table 3-9 Boolean Type

Name	Storage Size	Description
BOOLEAN	1 byte	Logical Boolean (true/false)

The valid literal value for representing the “true” state is TRUE. The valid literal for representing the “false” state is FALSE.

Note: The BOOLEAN data type can only be used for a variable declaration in an SPL program - it cannot be used to define a column data type in a table.